Pope Francis on Wednesday condemned administrators and criminals in Rome who allegedly pocketed public funds meant to help poor migrants, saying the city needed a "spiritual and moral renewal.''

Francis, who has made defense of the poor a trademark of his papacy, forcefully defended their rights in his homily at a New Year's Eve vespers service for thousands at St. Peter's Basilica.

He denounced situations where the poor were made to feel like criminals and "forced to behave like mafiosi" to defend themselves.

Earlier this month, police arrested 37 people suspected of being part of a "mafia-like'' organization that guided public contracts to people close to the alleged boss of the organization, a right-wing extremist with longtime ties to Rome's underworld.

The Italian media have dubbed the investigation, which is continuing, "Mafia Capital."

Some contracts involved running migrant centers and camps on Rome's poor outskirts. Investigators said funds were pocketed by corrupt city administrators and their criminal cohorts instead of being used to improve squalid conditions.

Francis is also the bishop of Rome, which is both the Italian capital and the center of Christianity. Calling it "our city," Francis said, "We have to defend the poor, not defend ourselves from the poor. We have to serve the weak, not use the weak."

In the current scandal, prosecution documents include transcripts of phone wiretaps that showed how those who won contracts often profited from serious social problems.

"Have you got any idea how much you can make out of immigrants?" one of those arrested said, referring to subsidies for providing services at temporary camps for migrants. "Drug trafficking brings in less."

After the arrests, Rome's mayor, Ignazio Marino, ordered a review of city contracts, and Prime Minister Matteo Renzi proposed tougher national laws against corruption.